Polishing and electroless nickel compositions, kits, and methods

ABSTRACT

Disclosed are various methods, kits, and compositions in the field of electroless nickel plating and chemical polishing. An electroless nickel plating composition may include a surfactant-brightener; a coupler; a bismuth metallic stabilizer; and organosulfur stabilizer and a bismuth complexer. Prior to plating, a substrate may be polished with a polishing composition that includes a surface blocker and a surface leveler. When practiced in accordance with the preferred teachings described herein, the electroless nickel plating composition is capable of providing a mirror-bright, lustrous finish, and has good leveling properties. The composition may be made without lead or cadmium.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/904,510, filed May 29, 2013, now U.S. Pat. No. 8,936,672, whichclaims benefit of U.S. Provisional Application No. 61/663,009, filedJun. 22, 2012, and U.S. Provisional Application No. 61/772,092, filedMar. 4, 2013, which are hereby incorporated herein by reference in theirentirety.

TECHNICAL FIELD

The present application generally is in the fields of chemical polishingand metal plating. Many embodiments are in the field of electrolessnickel plating and chemical polishing.

BACKGROUND

Numerous types of materials are often polished to impart variousqualities, including, but not limited to, a desired amount ofreflectivity and/or surface roughness. For example, in some cases it maybe desirable to brighten a material to have a mirror-like reflectivity,such as for ornamental appearances. Further, it may be desirable topolish the material to have a smooth surface, such as for minimizingwear on a moving part.

Traditionally, materials have been polished using mechanical means. Forexample, steel articles requiring a high degree of luster andreflectivity are usually polished using mechanical means including, butnot limited to, vibratory bowls, burnishing barrels, polishing latheswith belts, and tumbling media. However, such methods are not especiallyeffective for parts having complicated shapes or which are otherwisefragile. Other methods are also known, including electrochemical methodsfor polishing. However, these methods also may not be suitable forcomplicated parts and otherwise require expensive equipment to achievethe desired results.

Further, many plating methods are known in the art, which can be usedwith or without polishing. Plating can be used to provide bettercorrosion and/or wear resistance. In this regard, the material isgenerally plated or coated with a nobler metal.

Conventional plating techniques include, for instance, galvanic platingand electroless plating. In galvanic plating, an externally appliedelectric current is used in conjunction with a solution that containsmetal ions to thereby cause galvanic deposition of metal onto thesurface of an object to be plated. Electroless plating, in contrast,connotes plating from a solution that contains metal or metal ions,without the necessity of external electric current application.Electroless nickel plating generally employs a plating solution thatincludes nickel ions (typically Ni2+ in a sulfate solution) and areducing ion such as hypophosphite, and that typically further includesadjuncts such as complexing agents, buffering agents, and anti-pitagents. An object to be coated with nickel is introduced to the solutionand the solution is brought to an elevated temperature, whereupon thereducing agent reduces the nickel ions to form nickel metal (Ni⁰). Thiscauses the nickel metal to be plated onto the object.

A number of properties are desired of an electroless nickel platingsolution. In many embodiments, an electroless nickel plating solutionwill impart a bright or semi-bright surface finish on the object to beplated. Generally, it is desirable that the electroless nickel platingsolution be a low-pitting solution to mitigate against pits on thesurface of the plated object. The solution should have good agingproperties, by which is contemplated that, as the solution is consumedin use, the byproducts of the plating reaction, which include phosphatesand other byproducts, do not cause degradation of performance, dullingof the finish, or the like.

Another desired property is shelf stability. In many embodiments, anelectroless nickel plating solution is prepared in situ from twoprecursor solutions, one solution including nickels ions and the otherincluding the reducing agent. In such embodiments, it is desirable thatthe two precursor solutions be themselves shelf-stable.

Many heretofore known electroless nickel plating solutions employsignificant levels of lead or cadmium to assist in attaining one or moreof the above-noted desirable properties. More recently, it has becomedesired to reduce or eliminate lead, cadmium, and similar heavy metalsin light of toxicity and environmental concerns. Under the ROHSdirective (with reference to directive 2002/95/EC of the EuropeanParliament, Jan. 27, 2003), for example, lead, mercury, cadmium,hexavalent chromium, polybrominated biphenyls, and polybrominateddiphenyl ethers are limited or restricted in certain commercialapplications. In light of this ROHS directive and similar standards thatrestrict the use of lead and cadmium, it is desirable to provide anelectroless nickel plating solution that attains some or all of theabove-noted advantages without necessitating the inclusion of lead orcadmium.

SUMMARY

The invention provides, in various embodiments, methods and kits in thefield of electroless nickel plating and chemical polishing.

In one form, a chemical polishing composition and method are providedfor polishing a ferritic substrate. The composition includes a ferriticsurface blocker and a fluoridic surface leveler. The surface blockerincludes an oxidizing agent and a wetting agent and the surface levelerincludes a fluoride salt and an oxidant. The surface blocker and thesurface leveler are provided in amounts effective to polish a ferriticsurface. The chemical polishing composition and method may be used toreduce the roughness of the surface and also increase the reflectivity.Such a composition and method may be used with complex part geometrieswhere traditional polishing techniques are not suitable or fail toachieve the desired level of polishing.

According to one form, the fluoride salt is selected from the groupconsisting of sodium fluoride, potassium fluoride, lithium fluoride,calcium fluoride, ammonium bifluoride, and mixtures thereof. The oxidantmay be selected from the group consisting of ammonium nitrate, sodiumnitrate and potassium nitrate. The oxidizing agent may be selected fromthe group consisting of ammonium persulfate, sodium persulfate, hydrogenperoxide, sodium peroxide, and mixtures thereof.

In another form, the composition may further include an oxidizing acid,a complexer and a wetting agent. The oxidizing acid present in an amounteffective to drive ferritic removal and may be selected from the groupconsisting of sulfuric acid, nitric acid, phosphoric acid, hydrofluoricacid, fluoroboric acid, and methanesulfonic acid and mixtures thereof.The complexer may be present in an amount effective to inhibitredeposition of iron with the complexer being selected from the groupconsisting of citric acid, malic acid, lactic acid, succinic acid, andoxalic acid. The wetting agent may include a non-ionic or ionic typesurfactant.

In some forms, the chemical polishing composition and method may be usedas a precursor step to a further plating or coating process. Forexample, the chemical polishing process can be used prior to a nickelplating process, including conventional electroless nickel platingprocesses or the electroless nickel process described herein.

The chemical polishing composition and method may provide a number ofbenefits that increases the performance of plating or coating processes.For example, as the surface is smoother after polishing, with reducedmicroroughness, the orientation of the plated material may be improved.Further, the polished surface may include additional micro-active siteswhich may improve bonding between the surface and the plated material.These changes can lead to further benefits, such as requiring lessplating material, such as nickel, to be used in the plating process.Similarly, less energy is required in the process with lessenvironmental impact. Moreover, the polished and plated surface may havesignificantly improved reflectivity and corrosion performance than byplating alone.

Some aspects of the invention may be embodied in kits, or systems, thatinclude multiple compositions. In some embodiments, a kit for platingincludes a first container that includes a first composition and asecond container that includes a second composition. The firstcomposition contains nickel and the second composition contains areducing agent, such as hypophosphite. The first and second containersneed not be physically affixed to one another, but generally, the firstand second compositions are combinable to form an electroless nickelplating composition.

In some embodiments, the first composition includes asurfactant-brightener present in an amount effective to enhance lusterof an object plated with the electroless nickel plating compositionformed when the first and second compositions are blended together. Thefirst composition further includes a coupler present in an amounteffective to inhibit oil-out of the surfactant-brightener. In otherembodiments, not mutually exclusive with regard to the embodimentdescribed above, the second composition includes a bismuth metallicstabilizer in an amount effective to inhibit plate-out of theelectroless nickel plating composition and further includes a bismuthcomplexer being present in the amount effective to inhibit precipitationof bismuth.

In some embodiments, the invention contemplates method for preparing anelectroless nickel plating composition, the method including blendingfirst and second compositions, the first composition including nickeland the second composition including a reducing agent. The first or thesecond composition, or both compositions, may be as heretoforedescribed.

The kit may include a third container that includes a third composition.The third composition may include a reducing agent and at least one of apH buffer and an anti-pit agent. Generally, the second composition thatincludes a reducing agent also will include a pH buffer and/or ananti-pit agent. Where a third composition is provided, the proportion ofthe reducing agent to the buffer and/or anti-pit agent is different inthe third composition from this proportion in the second composition. Itis contemplated that the first and second compositions may be used as“makeup” compositions in the initial preparation of the electrolessnickel plating composition, while the first and third compositions maybe used as a replenisher composition to replenish hypophosphite.

In other embodiments, the invention contemplates a method forelectroless nickel plating. An electroless nickel plating compositionthat includes nickel and a reducing agent is provided, and to thiscomposition is introduced an object to be plated. The object to beplated is introduced to the electroless nickel plating composition underconditions sufficient to cause nickel to be plated onto a surface of theobject. In some embodiments, the electroless nickel plating compositionincludes a reducing agent, nickel, a surfactant-brightener, and acoupler. In other embodiments, not mutually exclusive with regard to theheretofore described embodiment, the electroless nickel platingcomposition includes a bismuth metallic stabilizer and a bismuthcomplexer. The method may contemplate replenishing the electrolessnickel plating composition with nickel and/or with a reducing agent.

In some embodiments, the invention contemplates a first electrolessnickel plating composition as described herein. In other embodiments,the invention contemplates a second or a third electroless nickelplating composition as described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a surface to be plated.

FIG. 2 is a cross-sectional view of the surface shown in FIG. 1illustrating irregularities in the surface topology.

FIG. 3 is a cross-sectional view similar to FIG. 2, showing the objectafter plating.

FIG. 4 is a representation of a cross sectional view of a surface to bepolished.

FIG. 5 is a representation of the surface shown in FIG. 4, illustratingblocking of the surface.

FIGS. 6 and 7 are a representation of the surface shown in FIG. 4 afterpolishing, showing the original etched surface in FIG. 6 in phantomlines.

The foregoing figures are representational views and are intended todepict the leveling phenomenon afforded by some embodiments of thepresent invention, and are not intended to represent the results of anyparticular example.

DETAILED DESCRIPTION

Generally, the embodiments described herein are contemplated to beuseful in connection with metal plating compositions, kits, and methods,including but not limited to nickel plating, and also including but notlimited to electroless nickel-plating. It is contemplated that in someembodiments one or more of the herein described polishing compositions,kits, or methods may be used in connection with galvanic or otherplating techniques. In other embodiments, it is contemplated that theherein described polishing compositions, kits, or methods may be used inconjunction with other metals for other metallic plating purposes. Whenused in connection with electroless nickel plating, however, certainembodiments of the disclosed polishing compositions, kits, or methodsare believed to provide various advantages as stated herein. Theinvention is not deemed to be limited to a composition, kit, or methodthat provides all of the stated advantages.

In one form, an optional chemical polishing method may be included priorto electroless nickel plating. Additionally or alternatively, thepolishing method may be performed with other forms of plating or withoutany plating whatsoever. In this regard, a chemical polishing compositionand method are provided that can be used on a number of differentmaterials, including, but not limited to, steel and related metals. Thechemical polishing composition may be used to decrease surfaceroughness, increase reflectivity and/or remove surface contaminants.

In one form, the chemical polishing composition may comprise a ferriticsurface blocker and a fluoridic surface leveler. The chemical polishingcomposition includes amounts of the ferritic surface blocker andfluoridic surface leveler effective to polish a ferritic surface.Without intending to be limiting, it is hypothesized that the surfaceblocker may help in filling and/or blocking valleys in the surface whileleaving peaks in the surface relatively unblocked. In this regard, thefluoridic surface leveler is then able to remove material from the peakswhile generally not removing significant amounts of material from thevalleys. Therefore, the overall roughness of the material is decreased.Further, the reflectivity of the surface may also be improved.

According to one embodiment, the ferritic surface blocker can includeone or more components including, but not limited to, an oxidizing agentand a wetting agent. The components in the ferritic surface leveler maybe prepared as a solution in advance or may be combined just prior to orduring use.

The oxidizing agent may include any number of different oxidizing agentssuitable for use in the chemical polishing composition. For example, theoxidizing agent may include ammonium persulfate, sodium persulfate,hydrogen peroxide, sodium peroxide, and mixtures thereof. The oxidizingagent may be used in the composition to provide a variety of functions,and is intended to block the surface of a substrate to be polished.While not intending to limit the invention to a particular theory ofoperation, it is believed that the oxidizing agent will cause anoxygen-containing layer to form on portions of the substrate. Theoxygen-containing layer may be a gaseous layer. The oxidizing agent maybe provided in any amount suitable for this purpose. In someembodiments, the concentration range is 0.5-4.0 mole/liter, and in somecases 1.0-3.0 mole/liter.

The wetting agent may include any suitable component, such as anon-ionic surfactant. The wetting agent may be used in the compositionto wet the surface to permit action by the oxidizing agent as discussedabove. In one form, the wetting agent is selected from the groupconsisting of dodecyl maltosides, ethoxylated amines, octylphenolethoxylates, and sodium ethylhexyl sulfate. The surfactant may bepresent in any amount suitable to wet the surface of the substrate. Insome embodiments, the surfactant concentration range is 0.005-2.0gram/liter, or preferred 0.01-0.5 gram/liter.

The fluoridic surface leveler may include one or more componentsincluding, but not limited to one or more fluoride salts and an oxidant.The fluoridic surface leveler may be used to remove material from thesurface to be polished. In this regard, the fluoridic surface levelermay include multiple components that provide varying levels ofaggressiveness for removing material. For example, the fluoridic surfaceleveler may include a bulk surface removing component that removesmaterial in a generally more aggressive manner to the overall surface orexposed surface. The fluoridic surface leveler may also include a moretargeted surface removing component that targets more specific sites ofthe surface. In other forms, the fluoridic surface leveler only includesa bulk surface removing component. In this regard, there is no targetedsurface material removing component and/or other components in thecomposition may provide more targeted surface material removal.

The fluoridic surface leveler includes a fluoride salt and an oxidant.The fluoride salt may comprise one or more of a variety of differentcomponents. For example, the fluoride salt may include sodium fluoride,potassium fluoride, lithium fluoride, calcium fluoride, ammoniumbifluoride, and mixtures thereof. The fluoride salt may be included in avariety of different amounts effective to polish the ferritic surface.For example, the fluoride salt may be present in the range of 0.1-4.0mole/liter, and in some embodiments 0.2-2.0 mole/liter. Similarly, theoxidant can include one or more of a number of different oxidantcomponents. For example, the oxidant may include ammonium nitrate,sodium nitrate, potassium nitrate, and mixtures thereof. The oxidantsmay be used in the composition to polish the ferritic surface and may bepresent in any amount effective for that purpose. For example, in oneform, the oxidant is present in the range of 0.05-2.0 mole/liter, insome cases 0.1-1.0 mole/liter.

The chemical polishing composition may also include a complexer orcomplexing agent. The complexer may include one or more components thehelp inhibit redeposition of iron. According to one form, the complexermay include citric acid, malic acid, lactic acid, succinic acid, oxalicacid and mixtures thereof. The complexer may be used in the compositionin an amount effective to inhibit redeposition of iron by forming acomplex with iron that has been removed from the surface of thesubstrate. The complexing agent may be provided in any amount effectivefor this purpose. For example, in one form, the complexing agent may beprovided in a range of 0.05-2.0 mole/liter, and in some cases 0.1-1.0mole/liter.

In one form, the chemical polishing composition may also include anoxidizing acid in an amount effective to drive ferritic removal byproviding acidity. The oxidizing acid may perform other functions in thecomposition. Any number of different oxidizing acids may be included,such as sulfuric acid, nitric acid, phosphoric acid, hydrofluoric acid,fluoroboric acid, and methanesulfonic acid, and mixtures thereof. Theoxidizing acid may be used in the composition in any suitable amount forthe intended purpose. The oxidizing acids may be provided, for example,in amounts in the range 0.05-2.0 mole/liter and in some cases 0.1-1.0mole/liter.

According to one form, the fluoride salt may utilized for dissolving(chemically attacking) a steel article since iron (Fe) ions eluted fromthe article may then be stabilized as complex ions of FeF₆ ³⁻ or thelike from the addition of the complexing agents. The exposed surface ischemically active and free of contaminants that affect furtherprocessing steps. This chemically pure surface has found to improveoverall adhesion of deposits.

The compositions described herein may be provided in the form of a kit,the kit containing a first and second container, and each containercontaining a portion of the polishing composition. The containers neednot be of any suitable form, but generally may be sealed or sealablecontainers to permit transport. The containers need not be physicallyconnected to one another. In some embodiments the first and secondcompositions may be concentrated, that is, they may contain a greaterproportion of the functional ingredients to water than would benecessary for the surface treatment process. “Concentrated” does notnecessarily connote or imply removal of water from a less concentratedcomposition. A kit that contains concentrated components in this formwill contain relatively less water than would be included when thecompositions are ready for commercial use, thus facilitating shippingand handling of the compositions. In many embodiments, the functionalingredients of the first and second composition will be present from5-25 times, preferably about 10 times, the amounts required in ordinarycommercial use.

The composition or kit may be used in a polishing method, by which asubstrate to be polished is introduced to a polishing composition for atime and under conditions effective to cause the surface to be polished.A number of factors may influence the polishing rate. For example, theratio of oxidizing acid to oxidizing agent may influence the polishingrate (i.e., metal dissolution rate) along with the solution temperature.In one form, at a constant bath temperature, as the acid concentrationincreases, so does the metal removal rate/polish rate. During chemicalpolishing, the reaction is exothermic thereby increasing the solutiontemperature which thus increases the polishing rate. In one form, wherethe concentration of the fluoride salt is more than 2 mol/L, it maybecome difficult to control the polishing rate, but if the concentrationis less than 0.2 mol/L, the polishing rate is less than 1 μm/min, suchthat the polishing efficiency may be too low. In one form, it ispreferable that the polishing rate is from 1 to 100 μm/min., whereby theconcentration of the fluoride salt is from 0.2 to 2 mol/l, to obtain thepreferable polishing rate. In one form, where the fluoride salt has aconcentration of from 0.3 to 1.5 mol/L, a practical polishing rate of 1to 50 μm/min is obtained, the polishing rate is readily maintained andcontrolled. The surface treatment solution temperature may be in anysuitable range. In some cases, the solution temperature is in the rangeof 55-110° F., and in some cases 70-90° F.

In one form, the chemical polishing composition includes ammoniumbifluoride in an amount of about 0.2 mole/liter to about 0.7 mole/liter,fluoroboric acid in an amount of about 0.1 mole/liter to about 0.5mole/liter, sodium nitrate in an amount of about 0.1 mole/liter to about0.5 mole/liter, oxalic acid in an amount of about 0.08 mole/liter toabout 0.16 mole/liter, hydrogen peroxide in an amount of about 1.0mole/liter to about 3.0 mole/liter and a surfactant in an amount ofabout 0.03 gm/liter to about 0.08 gm/liter. In such composition, it ishypothesized that the hydrogen peroxide and the surfactant may functionto block a portion of the surface as a result of the gassing of hydrogenperoxide. Further, it is hypothesized that the ammonium bifluoride willattack the surface in a gross manner while the sodium nitrate willattack the surface in a more fine fashion. Additionally, it is expectedthat the fluoroboric acid will help drive the reaction forward withacidity. Fluoroboric acid may be used as it is generally non-fuming,though other materials may also be used, it is believed that the oxalicacid will function as a complexer which will bind with iron ions andimpurities, thereby helping to keep them from redepositing on thesurface.

Referring to FIGS. 4-7, what is understood to be the operation of thechemical polishing composition will be discussed. As found in FIG. 4, across-section of a ferritic material 20, such as steel, is shown havingvarious peaks 22 and valleys 24. The number and size of the peaks andvalleys help define the relative roughness of the surface of theferritic material 20. Referring now to FIG. 5, a chemical polishingcomposition is combined with the ferritic material 20 such that asurface blocking layer 26 at least partially covers the ferriticmaterial 28. As seen in FIG. 5, the surface blocking layer 26 isgenerally positioned adjacent at least some of the valleys 24 whileleaving at least a portion of the peaks 22 exposed. It should be notedthat the surface blocking layer 26 may also cover the peaks 22, but thatthe relative thickness of the surface blocking layer 26 covering thepeaks 26 is thinner than the valleys 24.

The fluoridic surface leveler contacts and generally removes at least aportion of the peaks 26, as shown in dashed lines in FIG. 6. Theresulting polished surface is shown in FIG. 7 whereby the overallroughness of the ferritic material 20 has decreased relative to thestarting roughness shown in FIG. 4.

The following parameters are based on applications of the surfacetreatment on steel, and on additional applications of the surfacetreatment on steel with subsequent plating of the test panels. These areexemplary and are not intended to be limiting. The overall reflectivityas measured by utilizing methods DIN 65530/ASTM D523/ISO 2813/BS 3900,and employs the use of a TRI-GLOSS meter. While not limiting theinvention, it is believed that typical reflectivity measured in glossunits (GU) of processed steel through chemical polishing solutionincreased can increase 50-75% over the untreated materials. The surfaceroughness, which may be measured and tested utilizing test methodsoutlined in DIN 4728/4762, ISO/DIS 4287, employs the use of aprofliometer. Again without intending to limit the invention, it isbelieved that surface roughness (_(R)A) values may decrease (therebyindicating improved surface leveling) by 20-40% overall upon polishing.

In one form, the above-described polishing solutions can be used topolish a material such as steel. For example, a hardened steel articlecan be cleaned and neutralized and then polished utilizing theabove-described polishing solutions. The polishing solution can removeimpurities and smooth the surface to thereby improve adhesion of laterapplied coatings. For example, after polishing the material can becoated, such as using an electroless nickel process as described belowin more detail.

Heretofore the polishing composition, kits, and methods have beendescribed. Turning to the electroless nickel plating composition, kits,and methods, the embodiments are not meant to be mutually exclusive withregard to the polishing compositions, kits, and methods, but to thecontrary it is contemplated that a substrate may be polished and thenmay be caused to be plated with nickel via an electroless nickel platingprocess as described below.

In many embodiments, the invention provides an electroless nickelplating composition that is capable of providing a mirror-brightleveling, low-pit or pit-free nickel plating. The composition may beformulated to have good aging properties, such that the platingproperties remain sufficiently consistent through a bath life of 6-10metal turnovers (MTOs). The electroless nickel plating compositiongenerally may be formed in situ from first and second compositions, thefirst composition including nickel and the second composition includinghypophosphite or another reducing agent. In some embodiments, theelectroless nickel plating composition is formed other than via blendingof first and second compositions. When first and second compositions areemployed, they may be composed to be shelf-stable at room temperaturefor a period of at least two weeks. The electroless nickel platingcomposition may, if desired, include lead or cadmium, but preferably arefashioned without lead or cadmium but are able to accomplish themirror-bright deposit of nickel in the absence of lead and cadmium. Thecomposition may allow for plating at moderate solution pH, typically apH ranging from 4.0-7.0 and preferably 4.2-5.7, and moderate temperaturein the range of 135-210° F., preferably 145-195° F. In some embodiments,where the amount of nickel to be plated is not mandated byspecification, it is believed that less nickel will be required toresult in plating of comparable appearance than in certain conventionalprocesses.

The electroless nickel plating composition may be formed from twoprecursor “make-up” compositions noted herein as first and secondcompositions. The compositions described herein may be solutions with nosolid phase, or the composition may contain solid particles. Generally,the first composition includes nickel and the second compositionincludes hypophosphite or another reducing agent. Precursor compositionsmay be in a ready-to-use form or may be in the form of concentrates thattypically would be diluted with water, either before or after blendingtogether, for use with electroless nickel plating.

The first composition generally includes nickel, which is provided as apositive nickel ion (typically Ni²⁺). The nickel is supplied as thesulfate, chloride, sulfamate, acetate, or other suitable salt. Theelectroless nickel plating composition may include nickel in anysuitable amount, but preferably includes nickel in the range of 0.5-12gm/L, more preferably from 4-8 gm/L nickel. To achieve the foregoing,when a kit of first and second compositions is provided, theconcentration of nickel in the first composition may take any suitablerange, for instance a range of from 20-180 g/L Ni (metal), and in someembodiments from 50-130 g/L Ni (metal) The second composition includeshypophosphite, which may be supplied as sodium, potassium, or ammoniumsalt. Generally, the electroless nickel plating composition includes areducing agent in any suitable amount. When the reducing agent ishypophosphite, it may be used in the range of 20-40 gm/L sodiumhypophosphite, preferably 24-34 gm/L sodium hypophosphite. To achievethe foregoing, when a kit of first and second compositions is provided,the concentration of reducer in the second composition or thirdcomposition may range in any suitable amount, and preferably ranges from60-600 g/L sodium hypophosphite, more preferably 150-300 g/L sodiumhypophosphite.

The electroless nickel plating composition need not include, butpreferably does include, other adjuncts useful in connection withelectroless nickel plating. For example, the electroless nickel platingcomposition may include complexing agents, which generally are chelatorswhich are added to prevent the precipitation of nickel by the reactionproducts from the hypophosphite reaction of nickel ions. Typicalcomplexing agents include, for example, malic acid, lactic acid, citricacid, glycolic acid, succinic acid, glycine, and alike. The electrolessnickel plating composition may include a complexing agent in the rangeof from above 0.1-5.0 mol/L, preferably 1.0-3.0 mol/L, or any otheramount suitable to inhibit precipitation of nickel.

The electroless nickel may further include a pH buffering agent. This pHbuffering agent may be added in any amount suitable for pH buffering,preferably an amount from 2-20 gm/L, and more preferably 6-12 gm/L. Thebuffering agent may include, for instance, acetic acid, boric acid,citric acid, or the like. Some pH buffers also will provide complexing.For example, it is contemplated that citric acid will add to complexingand buffering properties.

The electroless nickel plating composition may further include ananti-pit agent. This is typically a low-foam, high-temperature-tolerantsurfactant which is added to reduce surface tension and to therebyreduce or eliminate clinging bubbles that may lead to pitting defects onthe surface. One suitable anti-pitting agent is NIAPROOF 08 sold byNiacet Corp. of Niagara Falls, N.Y. NIAPROOF 08 is believed to comprisesodium 2-ethylhexyl sulfate. Another suitable anti-pit agent is believedto be AEROSOL MA 80-1, sold by Cytec Industries of Woodland Park, N.J.AEROSOL MA 80-1 is believed to comprise sodium dihexyl sulfosuccinate.Other suitable anti-pit surfactants as are common the nickel platingindustry or otherwise found to be suitable may be employed. Such agentsmay be used in any suitable amount, typically a range of 0.01 gm/L to 1gm/L, and more preferably 0.05-0.5 gm/L.

The electroless nickel plating composition further may include an oxygenstabilizer. When an oxygen stabilizer is employed, any suitable oxygenstabilizer may be used. One suitable oxygen stabilizer is believed to bepotassium iodate. The oxygen stabilizer is believed to add stability andto inhibit decomposition of the electroless nickel plating composition.The oxygen stabilizer may be used in any amount suitable for thispurpose, such as a range of 0.5-600 mg/L, preferably 5-300 mg/L.

The heretofore described complexing agents, pH buffering agents,anti-pit agents, and oxygen stabilizer may be present in one or both ofthe first and second compositions that are used to prepare electrolessnickel plating composition. When the electroless nickel platingcomposition is prepared from first and second “makeup” compositions asdescribed herein, one or a combination of these components may bepresent in the first composition, and one or a combination of thesecomponents may be present in the second composition. When a thirdcomposition for replenishment of reducing agent is provided, some or allof these components may be provided in the third composition.

The electroless nickel plating composition, and precursor compositions,preferably are formulated in the substantial or complete absence of leadand in the substantial or complete absence of cadmium. Levels of leadand cadmium preferably are sufficiently low as to be undetectable. It ispossible that some embodiments of the inventive electroless nickelcomposition, or precursor compositions, will include trace amounts oflead or cadmium. It is contemplated that in other embodiments it may bedesirable to include functional amounts of lead or cadmium. Generally,however, in many embodiments it is preferred that the composition beROHS-compliant and that levels of lead and cadmium be as low aspossible.

The electroless nickel plating composition may include a metallicstabilizer, generally a bismuth metallic stabilizer. This stabilizer isadded to inhibit spontaneous plate-out of the nickel in the compositionand is believed to contribute to low-level brightness. This is believedto be due to the tendency of the metallic stabilizer to codeposit withthe nickel. When employed, the metallic stabilizer should be used in anysuitable amount effective to inhibit spontaneous plate-out. It isbelieved that in the electroless nickel plating composition a suitableamount will range from 0.1-7.0 mg/L, preferably 0.2-3.5 mg/L. Theconcentration of bismuth in the precursor second composition or in thethird composition may take any suitable range, and for instance mayrange from 0.5-300 mg/L Bi (metal), preferably 5-150 mg/L Bi (metal). Insome embodiments, it is contemplated that the bismuth metallicstabilizer may be present in the first composition, or in all threefirst, second, and third compositions.

When the metallic stabilizer is employed, the electroless nickel platingcomposition preferably includes a bismuth complexer. The bismuthcomplexer is an ingredient that is believed to form a stable solublecomplex compound with bismuth and thereby to inhibit the precipitationof bismuth in the plating solution and in concentrate products. Onesuitable bismuth complexer is sodium nitrilotriacetate (NTA sodiumsalt), which is believed to form the complex bismuth sodiumtriglycollamate. The bismuth complexer may be employed in any amountsuitable for this purpose, preferably an amount ranging from 2-500 mg/Land preferably 5-200 mg/L in the electroless nickel plating composition.The concentration of bismuth complexer in the precursor secondcomposition or in the third composition may be any suitable amount. Forexample, NTA sodium salt may be present in the second or thirdcomposition in an amount ranging from 10-20,000 mg/L NTA sodium salt,preferably 50-5,000 mg/L NTA sodium salt. Again, in some embodiments itis contemplated that the bismuth complexer may be present in the firstcomposition, or in all three first, second, and third compositions.

The electroless nickel plating composition further may include anorganosulfur stabilizer. The organosulfur stabilizer is a sulfur-basecomposition that is believed to prevent or inhibit spontaneous plate-outof the composition and to contribute grainy low level luster to thecomposition. Suitable organosulfur stabilizers include for instance,thiourea, thioglycolic acid, mercaptobenzothiazole, thiuronium,methiomine, thiocyanate, and mixtures thereof. When employed in theelectroless nickel plating composition, the organosulfur stabilizer ispreferably present in an amount sufficient to inhibit spontaneousplate-out. It is believed that suitable amounts range from 0.05-5.0mg/L, preferably 0.1-2.0 mg/L. To achieve this, the concentration oforganosulfur stabilizer in the second or third compositions may be anysuitable amounts, for instance 0.25-500 mg/L organosulfur stabilizer,preferably 0.5-200 mg/L organosulfur stabilizer. In some embodiments itis contemplated that the organosulfur stabilizer may be present in thefirst composition, or in all three first, second, and thirdcompositions.

The electroless nickel plating composition further may include asurfactant-brightener. This is a nonionic surfactant which is believedto contribute mirror-bright properties and leveling characteristics. Thesurfactant-brightener may be, for example, selected from among nonyl andoctyl-phenoxypolyethoxyethanol having an HLB (hydrophilic/lipophilicbalance) in the range of about 12.0-18.0. When employed, thesurfactant-brightener should be used in any amount effective to enhanceluster of an object plated with the electroless nickel platingcomposition. It is believed that suitable amount in the electrolessnickel plating composition will range from 0.5-500 mg/L, preferably1.0-100 mg/L. When provided the first composition or in the thirdcomposition, the concentration of the surfactant-brightener may be anysuitable amount, for instance, 5-10,000 mg/L surfactant-brightener, andpreferably 10-2000 mg/L surfactant-brightener. In some embodiments, itis contemplated that the surfactant-brightener may be present in thesecond composition or in the third composition.

The surfactant-brightener is believed to have a tendency to rapidly“oil-out” of the plating solution in some instances, which can lead tocloudy-streaked deposits and less than desired plating properties. Whenused, the surfactant-brightener preferably is employed in conjunctionwith a coupler. The coupler is an anionic dispersant which is providedin any amount effective to inhibit oil-out of the surfactant-brightener.A suitable anionic dispersant may be selected from naphthalenesulfonates, such as alkali or alkyl naphthalene sulfonate. In someembodiments, the coupler may contribute low-luster brightness to theelectroless nickel plating composition. When employed, the coupler maybe used in any suitable amount, typically 10-2000 mg/L and preferably20-500 mg/L. The concentration of the coupler in the first precursorcomposition or in the third composition may be any suitable amount, forinstance, 50-20,000 mg/L coupler and preferably 100-10,000 mg/L coupler.In some embodiments, it is contemplated that the coupler may be presentin the second composition or in the third composition.

Some or all of the forgoing materials preferably are provided in theelectroless nickel plating composition. As heretofore described, theelectroless nickel plating composition may be prepared in situ by theplater from one or more precursor compositions, including a first makeupcomposition that comprises nickel and a second makeup composition thatcomprises a reducer. The first composition may be contained in a firstcontainer and the second composition may be contained in a secondcontainer. In many embodiments, the first composition will include asurfactant-brightener and a coupler, and the second composition willinclude a bismuth metallic stabilizer and a bismuth complexer andoptionally an organosulfur stabilizer. It is contemplated in otherembodiments that the first composition may include the bismuth metallicstabilizer and the bismuth complexer and optionally the organosulfurstabilizer and the second composition may include thesurfactant-brightener and coupler.

The first and second compositions may be provided in the form of a kit,or system, that includes first and second containers, namely, a firstcontainer that contains the first composition and a second containerthat contains the second composition. The containers need not be of anysuitable form, but generally may be sealed or sealable containers topermit transport. The containers need not be physically connected to oneanother. In some embodiments the first and second compositions may beconcentrated, that is, they may contain a greater proportion of thefunctional ingredients to water than would be necessary for platingpurposes. “Concentrated” does not necessarily connote or imply removalof water from a less concentrated composition. A kit that containsconcentrated components in this form will contain relatively less waterthan would be included when the compositions are ready for commercialuse, thus facilitating shipping and handling of the compositions. Inmany embodiments, the functional ingredients of the first and secondcomposition will be present from 5-25 times, preferably about 10 times,the amounts required in ordinary commercial use for plating purposes.

In use, the plater may receive a kit that includes first and secondcompositions as described herein. If the kit is provided in aconcentrated form, the plater may add water to achieve the desiredconcentration of functional ingredients. This addition of water mayoccur before or after blending the first and second compositionstogether to form an electroless nickel plating composition. For use inan electroless plating process, an object to be plated, such as aplastic or metallic object, is introduced to the electroless nickelplating composition. The pH of the electroless nickel platingcomposition preferably is or is brought to a pH of around 4.0-7.0, morepreferably 4.2-5.7, and the electroless nickel plating composition isbrought to a temperature in the range of about 135° F. to 210° F.,preferably 145° F. to 195° F. Via the chemical reduction of nickel ions,the object to be plated will become coated with nickel. Periodically, itmay be necessary to replenish the electroless nickel plating compositionwith nickel and with reducing agent. This is particularly true as thenickel solution is aged through more than 0.2 MTO. In replenishing theelectroless nickel plating composition, any suitable compositions thatemploy nickel and that employ a reducing agent, respectively, may beemployed. In many embodiments, the first composition may be employed toreplenish the electroless nickel plating composition with nickel, andthe second composition may be employed to replenish the electrolessnickel plating composition with the reducing agent. Preferably, a thirdcomposition that includes a reducing agent also may be employed and maybe included in connection with a kit as heretofore described. The thirdcomposition may include a reducing agent and one or more of the otheradjuncts, such as a buffering agent or anti-pit agent, in differentproportions than are found in the second composition. This is becausethe rate at which the reducing agent is consumed may be different fromthe rates at which one or more of the other ingredients are consumed orinactivated during the electroless nickel plating composition. Whenprovided as a third composition, the functional components may beemployed at a higher concentration, such as 2-50 times or preferably5-25 times the amount of reducing agent, that may be used in ordinarycommercial use. The other components may be present in greater or lesseramounts as may be found desirable or suitable.

The electroless nickel plating composition may include other components,such as other adjuncts or other functional components, which may beemployed for any purpose suitable to achieve the intended purposes ofsuch component.

It is believed that the electroless nickel plating compositionsdescribed herein will exhibit leveling. With reference to the Figures,for instance, a rough and irregular surface 10 is shown. This surfacehas visible imperfections, and, upon plating, it will be desirable tosmooth these imperfections such that the plated surface is more even andless irregular. As seen in FIG. 3, when the plating 12 is applied, thesurface becomes more smooth and less irregular.

The following parameters are based on applications of the mirror-bright,leveling electroless nickel, described in this application, deposited onsteel test panels with no prior surface treatment. These parameters areexemplary and are not intended to be limiting. By utilizing theelectroless nickel procedure, the reflectivity and surface condition ofthe treated materials can be significantly improved. In one form, theimprovement is a function of thickness coating. It was unexpectedlyfound that coatings with thicknesses greater than 2 μm will suffice incomparison to conventional electro-plated coatings that typicallyrequire coating thicknesses in excess of 20 μm. The electroless nickeldeposit can be used to provide a uniform, micro-leveling, surfacebrightening affect that improves overall reflectivity 60-80% overconventional electroless nickel systems. In other forms, the overallreflectivity can be improved by about 80-100%. Similarly, surfaceroughness conditions can be improved (decreased values) from 20-40% inmeasured rA (surface roughness) readings.

In another form, when the chemical polishing procedure is utilized priorto mirror-bright, leveling electroless nickel coating, steel sampleshave shown a 70-100% improvement in both the rA (surface roughness) andtotal gloss/reflectivity (measured in GU) compared to utilizing just oneof the chemical polishing and electroless nickel procedures separately.In one form, when used in combination as outlined above, the steelsamples had excellent adhesion, uniform coverage, reflectivity, surfaceroughness, wear and corrosion resistance regardless of the complexity ofthe shape. The corrosion resistance compared with conventional polishednickel systems improved from several hours utilizing conventional nickelto 120 hrs. of saltspray protection as outlined in method ASTM B-117.

It should be understood that the chemical polishing solution and methodsmay be used with other forms of coating or plating. For example, whileit has been found that the chemical polishing described above can beuseful with the particular forms of electroless nickel plating describedabove, it should be understood that the chemical polishing may also beused with other forms of electroless. Further, the chemical polishingmay be used with other forms of coating or plating, such as electrolyticcoating.

The following Examples are provided to illustrate certain embodiments ofthe invention, but are not intended to limit the invention in scope.

EXAMPLES

Solution A was used in connection with Examples 1 and 2 and withComparative Examples 1 and 2. This solution was composed of water andNickel sulfate hexahydrate, with the nickel sulfate hexahydrate added inthe amount of 270 gm/L (correlating to 60 gm/L nickel). This hexahydratewas added as a powder.

Comparative Example 1

To a 100 mL sample of Solution A was added 1 mL of 10 gm/L IGEPAL CO-630(nonyl-phenoxypolyethoxyethanol HLB 13.0). A permanent cloudy solutionformed, thus indicating oil-out of the surfactant.

Example 1

To a 100 mL, sample of Solution A was added 1 mL of 10 gm/L IGEPALCO-630 plus 60 gm/L RHODACAL N (Naphtalene sulfonate coupler). Theresulting solution remained clear green, thus indicating that thesolution was homogeneous and stable. This solution contained 100 mg/L ofIGEPAL CO-630, 600 mg/L of RHODACAL N, and 60 gm/L nickel.

Comparative Example 2

To a 100 mL sample of Solution A was added 1 mL of 10 gm/L IGEPAL CA-630(octyl-phenoxypolyethoxyethanol HLB 13.0). A permanent cloudy solutionformed, thus indicating oil-out of the surfactant.

Example 2

To a 100 mL sample of Solution A was added 1 mL of 10 gm/L IGEPAL CA-630pins 60 gm/L RHODACAL N (naphthalene sulfonate coupler). The resultingsolution remained clear green, thus indicating that the solution washomogeneous and stable. This solution contained 100 mg/L of IGEPALCA-630, 600 mg/L of RHODACAL N, and 60 gm/L nickel.

Solution B was used in connection with Example 3 and Comparative Example3. This solution was composed of sodium hypophosphite monohydrate addedto water in the amount of 300 gm/L.

Comparative Example 3

To a 100 mL sample of Solution B was added 1 mL of 10 gm/L BismuthNitrate Pentahydrate and 1 mL of 3 gm/L thiourea. After 24 hours ofstorage, the clear solution became cloudy grey indicating theprecipitation of insoluble bismuth sulfide particles.

Example 3

To a 100 mL sample of Solution B was added 1 mL of 50 gm/L sodiumnitrilotriacetate, 1 mL of 10 gm/L bismuth nitrate Pentahydrate, 1 mL of3 mg/L thiourea. After 2 weeks of storage, the solution remainedwater-clear with no precipitation of bismuth.

Solution C was used in connection with Examples 4-6 and in connectionwith Comparative Examples 4-6. This solution had the followingcomposition and a pH of 5.0.

TABLE 1 Nickel Sulfate Hexahydrate 30 g/L Lactic Acid 15 g/L Malic Acid15 g/L Glycine 5 g/L Acetic Acid 5 g/L Boric Acid 5 g/L SodiumHypophosphite 30 g/L Potassium Iodate 0.02 g/L Sodium Nitrilotriacetate0.04 g/L

In the following examples, low-carbon polished steel test panels 3″ by4″ were cleaned and acid activated in a 50% hydrochloric acid solution,then thoroughly rinsed with deionized water and immersed in theelectroless nickel plating solution for 1 hour at 190° F. After plating,the nickel-plated test panels were rinsed with deionized water and hotair dried. The plating deposit thickness was measured and the panelappearance was evaluated.

Comparative Example 4

To 1 liter of Solution C was added 5 mg of bismuth nitrate pentahydratehydrate, 0.3 mg of thiourea, and 20 mg of octyl-phenoxypolyethoxyethanolIGEPAL CA-630. The nickel deposit thickness was 0.00080 inches and thepanel appearance was bright with low luster, no leveling, and somecloudiness from oil out of the Surfactant Brightener I.

Example 4

An addition of 100 mg of RHODACAL N was made to the solution ofComparative Example 4. The nickel and hypophosphite concentrations werereplenished by analysis and additions, and the pH was adjusted back to5.0 with 50% ammonium hydroxide. After plating, the nickel depositthickness was 0.00084 inches and the panel appearance was mirror brightwith no cloudiness or streaking.

Comparative Example 5

To a fresh 1 liter of Solution C was added, 0.5 mg of thiourea, 20 mg ofIGEPAL CA-630, 100 mg of RHODACAL N and no bismuth. The nickel depositthickness was 0.00086 inches and the panel appearance was uniform lowluster brightness with no cloudiness or hazing.

Example 5

An addition of 5 mg of bismuth nitrate pentahydrate was made to thesolution of Comparative Example 5. The nickel and hypophosphiteconcentrations were replenished by analysis and additions and the pH wasadjusted back to 5.0 with 50% ammonium hydroxide. After plating, thenickel deposit thickness was 0.00084 inches and the panel appearance wasuniform mirror bright with no cloudiness or streaking.

Comparative Example 6

To a fresh 1 liter of Solution C was added 5 mg of bismuth nitratepentahydrate, 20 mg of IGEPAL CA-630, 100 mg of RHODACAL N and nothiourea. The nickel deposit thickness was 0.00078 inches and the panelappearance was uniform semi-bright with some graininess and no leveling.

Example 6

An addition of 0.3 mg of thiourea was made to the solution ofComparative Example 6. The nickel and hypophosphite concentrations werereplenished and the pH was adjusted to 5.0 with 50% ammonium hydroxide.After plating, the nickel deposit thickness was 0.00085 and the panelappearance was uniform mirror bright with no cloudiness or streaking.

Example 7

Example 7 was prepared with numerous samples to compare the effect ofdifferent concentrations of various ingredients during the chemicalpolishing process. Each of the sample solutions were tested on steelpanels which are pre-scratched on one side from the manufacturer. Thesteel is CRS SAE 1008/1010 that is 0.032″ thick (0.8 mm) with a groundfinish on one side. The steel panels are washed in a mild detergent,rinsed and then polished using the chemical polishing compositions. Thesteel panels were chemically polished using the compositions andprocessing times as shown in Table 2. The gloss (per the gloss meter)and surface roughness (per the profilometer) for each of the samplecompositions is shown in Table 3. The samples were polished, but werenot plated.

TABLE 2 Treatment Solutions and Processing Conditions for Example 7(Concentrations given in g/l) Ammonium Sodium Oxalic HydrogenFluoroboric Immersion Sample bifluroide nitrate acid Surfactant PeroxideAcid ° F. Time 7-1 14.97 12.00 3.00 0.03 160.00 40.00 75 30 Sec 7-214.97 12.00 3.00 0.03 160.00 40.00 75 60 Sec 7-3 29.94 24.00 6.00 0.06160.00 40.00 75 30 Sec 7-4 29.94 24.00 6.00 0.06 160.00 40.00 75 60 Sec7-5 29.94 24.00 6.00 0.06 160.00 40.00 75 120 Sec  7-6 37.43 30.00 7.500.08 160.00 40.00 75 30 Sec 7-7 37.43 30.00 7.50 0.08 160.00 40.00 75 60Sec 7-8 29.94 24.00 6.00 0.06 240.00 60.00 75 30 Sec

TABLE 3 Gloss and Surface Roughness of Polished Steel Panels GLOSSPROFILOMETER (Gloss Units GU) (Roughness Average _(R)A) UnscratchedPrescratched Unscratched Prescratched Side of Test Side of Test Side ofTest Side of Test Sample Panel Side A Panel Side B Panel Side A PanelSide B 7-1 41 27 0.78 0.96 7-2 27 52 0.88 0.95 7-3 60 35 0.63 0.99 7-441 57 0.75 0.86 7-5 106 138 0.42 0.57 7-6 110 125 0.37 0.46 7-7 118 1340.33 0.4 7-8 75 49 0.77 0.89

The results found in Table 3 show the unscratched side as side “A” whilethe prescratched side as side “B”. As found in Table 3, not only doesthe breakdown of the chemical polishing impact the gloss and surfaceroughness, but the exposure time also impacted the gloss and surfaceroughness. The gloss measurement was made using a standard glossmeterwhile the surface roughness was determined using a contact profilometer.The higher the gloss number, the higher the gloss, while the higher theprofilometer number, the larger the surface roughness. In one form, itis desirable to increase the gloss while reducing the surface roughness.It should be understood that the breakdown of the chemical polishingcomposition and the processing time can be modified to achieve thedesired gloss and surface roughness.

All of the above results (Table 3) characterize the benefits of thedescribed surface treatment application on steel, without nickelplating.

Example 8

In Example 8, a number of different nickel coatings were compared, withand without chemical polishing prior to the nickel coatings. The sametype of steel panels from Example 7 were used in Example 8 to comparethe different compositions and processes. Nine different combinations ofprocesses, coatings and chemical polishing steps were compared as shownin Tables 4, 5 and 6. The nickel coating processes used in the samplesdiffered in a number of ways.

Sample 8-1 was prepared without chemical polishing. Sample 8-1 wasnickel coated by plating in a non-leveling conventional electrolessnickel solution, Accu-Labs 392 (available from Accu-Labs, Inc. ofChicago, Ill.), for a plating time of 20 minutes.

The sample 8-2 was prepared without chemical polishing. Sample 8-2 wasnickel coated by electrolytic plating in a conventional high-chloridewatts nickel plating solution to produce a bright nickel deposit. Thenickel plating solution included: 90 gram/liter nickel chloride; 285gram/liter nickel sulfate; 45 gram/liter boric acid; 2 gram/litersaccharin; 5 mL/liter Accu-Labs NILUX NXZ Brightener Additive; 20mL/liter Accu-Labs NILUX Z-2 Carrier Additive (both available fromAccu-Labs, Inc. of Chicago, Ill). The test panel was plated for 10minutes using a hull cell.

Sample 8-3 was prepared without chemical polishing. Sample 8-3 wasnickel coated by electrolytic plating in a conventional low-chloridewatts nickel plating solution to produce a bright nickel deposit. Thenickel plating solution included 45 gram/liter nickel chloride; 285gram/liter nickel sulfate; 45 gram/liter boric acid; 2 gram/litersaccharin; 5 mL/liter Accu-Labs NILUX NXZ Brightener Additive; 20mL/liter Accu-Labs NILUX Z-2 Carrier Additive. The test panel was platedfor 10 minutes using a hull cell.

Sample 8-4 was prepared without chemical polishing. Sample 8-4 wasnickel coated by electrolytic plating in a conventional bright nickelsulfamate plating solution to produce a bright nickel deposit. Thenickel sulfamate plating solution included: 315 grams/liter nickelsulfamate; 22.5 gram/liter nickel bromide; 45 gram/liter boric acid; 10mL/liter Accu-Labs NILUX SNS Brightener Additive; 40 mL/liter Accu-LabsNILUX SNS Carrier Additive. The test panel was plated for 10 minutesusing a hull cell.

Samples 8-5 and 8-6 were prepared without chemical polishing. Sample 8-5and 8-6 were nickel coated in a mirror-bright, leveling electrolessnickel plating solution as described in Table 1 and including thechemical additives described in Comparative Example 4 and Example 4. Aone liter solution of the mirror-bright leveling electroless nickelsolution at 190° F. and pH 4.8 was used to nickel coat the sample panelsfor the times listed on Table 4.

Samples 8-7, 8-8 and 8-9 were all processed with the chemical polishsolution before nickel coating with the mirror-bright levelingelectroless nickel solution. The chemical polish solution used forsurface treatment of the Samples 8-7, 8-8 and 8-9 was the same asdescribed for Sample 7-5 in Table 2. The times for surface treatment ofeach panel are given in Table 4. The subsequent nickel coating ofSamples 8-7, 8-8 and 8-9 was produced by using the mirror-brightleveling electroless nickel solution described in Table 1 and includingthe chemical additives described in Comparative Example 4 and Example 4,at 190° F. and pH 4.8. The times used to nickel coat samples 8-7, 8-8and 8-9 are given in Table 4.

TABLE 4 Gloss Meter Results for Nickel Coatings Example 8 Gloss MeterResults (Gloss Units GU) PERCENT DIFFERENCE CALCULATIONS PANELDESCRIPTION A SIDE B SIDE Steel Chemical Nickel Plating PlatingUnscratched Prescratched Difference % Difference Polish Before CoatingTime Solution Untreated After Untreated After A B A B Sample PlatingSolution (mins) Age (MTO) Unplated Plating Unplated Plating side sideside side 8-1 None Electroless 20 5 17 19 25 15 2 −10 11.76 −40.00Non-Leveling 8-2 None Electrolytic 10 NA 15 51 13 49 36 36 240.00 276.92High-Chloride 8-3 None Electrolytic 10 NA 14 25 13 22 11 9 78.57 69.23Low-Chloride 8-4 None Electrolytic 10 NA 16 30 12 20 14 8 87.50 66.67Sulfamate 8-5 None Electroless 20 5 15 31 12 35 16 23 106.67 191.67Bright-Leveling 8-6 None Electroless 30 5 17 63 14 79 46 65 270.59464.29 Bright-Leveling 8-7 60 sec Electroless 20 5 21 107 14 109 86 95409.52 678.57 Bright-Leveling 8-8 45 sec Electroless 20 5 13 87 14 80 7466 569.23 471.43 Bright-Leveling 8-9 30 sec Electroless 20 5 18 91 15 9573 80 405.56 533.33 Bright-Leveling

TABLE 5 Profilometer (Roughness) Measurements for Nickel CoatingsExample 8 Profilometer Results (Roughness _(R)A) PERCENT DIFFERENCECALCULATIONS PANEL DESCRIPTION A SIDE B SIDE Steel Chemical NickelPlating Plating Unscratched Prescratched Difference % Difference PolishBefore Coating Time Solution Untreated After Untreated After A B A BSample Plating Solution (mins) Age (MTO) Unplated Plating UnplatedPlating side side side side 8-1 None Electroless 20 5 1.19 1.34 0.960.72 0.15 −0.24 12.61 −25.00 Non-Leveling 8-2 None Electrolytic 10 NA1.33 1.08 1.01 0.81 −0.25 −0.2 −18.80 −19.80 High-Chloride 8-3 NoneElectrolytic 10 NA 1.31 1.27 1.1 0.94 −0.04 −0.16 −3.05 −14.55Low-Chloride 8-4 None Electrolytic 10 NA 1.25 1.33 1.04 0.94 0.08 −0.16.40 −9.62 Sulfamate 8-5 None Electroless 20 5 1.53 1.24 1.02 0.91 −0.29−0.11 −18.95 −10.78 Bright-Leveling 8-6 None Electroless 30 5 1.23 0.880.84 0.66 −0.35 −0.18 −28.46 −21.43 Bright-Leveling 8-7 60 secElectroless 20 5 1.23 0.61 0.95 0.45 −0.62 −0.5 −50.41 −52.63Bright-Leveling 8-8 45 sec Electroless 20 5 1.3 0.59 0.85 0.2 −0.71−0.65 −54.62 −76.47 Bright-Leveling 8-9 30 sec Electroless 20 5 1.28 0.60.89 0.55 −0.68 −0.34 −53.13 −38.20 Bright-Leveling

TABLE 6 Nickel Coating Thickness Example 8 THICKNESS (A-side) SampleNickel Coating Micro-Inches 8-1 Electroless Non-Leveling 244 8-2Electrolytic High-Chloride 533 8-3 Electrolytic Low-Chloride 580 8-4Electrolytic Sulfamate 520 8-5 Electroless Bright-Leveling 230 8-6Electroless Bright-Leveling 368 8-7 Electroless Bright-Leveling 231 8-8Electroless Bright-Leveling 258 8-9 Electroless Bright-Leveling 260

TABLE 7 Corrosion Resistance Test Results Example 8 Salt Spray Hrs. ToRed Rust (RR) 24 48 72 96 Sample Nickel Coating HRS HRS HRS HRS 8-1Electroless Non-Leveling RR RR RR RR 8-2 Electrolytic High-Chloride RRRR RR RR 8-3 Electrolytic Low-Chloride RR RR RR RR 8-4 ElectrolyticSulfamate RR RR RR RR 8-7 Electroless Bright-Leveling NC NC NC NC 8-8Electroless Bright-Leveling NC NC NC NC 8-9 Electroless Bright-LevelingNC NC Trace Trace Salt spray per ASTM B-117; NC = No Corrosion, RR =Rust Failure, Trace = Less than 0.2% of surface with detectable redrust.

As found in Tables 4-6, the samples which were chemically polished priorto nickel plating achieved significantly improved gloss with reducedsurface roughness compared to other samples. Moreover, the chemicallypolished samples were able to achieve such properties with decreasedthickness. In other words, the chemically polished samples required lessnickel to achieve the gloss and surface roughness properties.

Typically, to achieve the gloss and surface roughness propertiesachieved in the above examples, it is necessary to mechanically polishthe steel surface and/or to use significant amounts of nickel. In oneform, the present combination of chemical polishing and electrolessnickel plating is able to achieve improved gloss and surface roughnesswhile also reducing overall nickel coating by at least about 50%.Moreover, the processes are not limited by the geometries of the partsthat are being polished and coated. The chemical polishing andelectroless nickel plating processes are suitable for use with partshaving complicated geometries and are capable of reacting with surfacesthat would otherwise be difficult to reach with mechanical polishingand/or would be difficult to plate using a nickel process that requireselectricity. Moreover, in one form, the chemical polishing andelectroless nickel plating processes are suitable with fragile partswhere mechanical polishing could cause damage and traditional polishingmay result in an undesired build up of plated nickel.

It is thus seen that the invention provides, in various embodiments,kits, methods, and compositions useful in the field of electrolessnickel plating. In many embodiments, the kits, methods, and compositionsprovide good electroless nickel plating characteristics, and are ROHScompliant.

All references cited herein are hereby incorporated by reference intheir entireties.

Uses of singular terms such as “a,” “an,” are intended to cover both thesingular and the plural, unless otherwise indicated herein or clearlycontradicted by context. The terms “comprising,” “having,” “including,”and “containing” are to be construed as open-ended terms. Anydescription of certain embodiments as “preferred” embodiments, and otherrecitation of embodiments, features, or ranges as being preferred, orsuggestion that such are preferred, is not deemed to be limiting. Theinvention is deemed to encompass embodiments that are presently deemedto be less preferred and that may be described herein as such. Allmethods described herein can be performed in any suitable order unlessotherwise indicated herein or otherwise clearly contradicted by context.The use of any and all examples, or exemplary language (e.g., “such as”)provided herein, is intended to illuminate the invention and does notpose a limitation on the scope of the invention. Any statement herein asto the nature or benefits of the invention or of the preferredembodiments is not intended to be limiting. This invention includes allmodifications and equivalents of the subject matter recited herein aspermitted by applicable law. Moreover, any combination of theabove-described elements in all possible variations thereof isencompassed by the invention unless otherwise indicated herein orotherwise clearly contradicted by context. The description herein of anyreference or patent, even if identified as “prior,” is not intended toconstitute a concession that such reference or patent is available asprior art against the present invention. No unclaimed language should bedeemed to limit the invention in scope. Any statements or suggestionsherein that certain features constitute a component of the claimedinvention are not intended to be limiting unless reflected in theappended claims. Neither the marking of the patent number on any productnor the identification of the patent number in connection with anyservice should be deemed a representation that all embodiments describedherein are incorporated into such product or service.

The invention claimed is:
 1. A kit comprising: a first containercontaining a first composition and a second container containing asecond composition, said first composition containing nickel and saidsecond composition containing a reducing agent, said first and secondcompositions being combinable to form an electroless nickel platingcomposition; said first composition containing a surfactant-brightener,said surfactant-brightener being present in an amount effective toenhance luster of an object plated with said electroless nickel platingcomposition, and a coupler, said coupler being present in an amounteffective to inhibit oil-out of said surfactant-brightener.
 2. A kitcomprising: a first container containing a first composition and asecond container containing a second composition, said first compositioncontaining nickel and said second composition containing a reducingagent, said first and second compositions being combinable to form anelectroless nickel plating composition; said second compositioncontaining a bismuth metallic stabilizer in an amount effective toinhibit plate-out of said electroless nickel plating composition, and abismuth complexer, said bismuth complexer being present in an amounteffective to inhibit precipitation of bismuth.
 3. A kit according toclaim 2, said second composition further containing an organosulfurstabilizer in an amount effective to inhibit plate-out of saidelectroless nickel plating composition.
 4. A kit according to claim 1,said surfactant-brightener being selected from the group consisting ofnonyl and octyl-phenoxypolyethoxyethanol surfactants having an HLBranging from about 12.0 to about 18.0.
 5. A kit according to claim 1,said coupler being selected from the group consisting of naphthalenesulfonates.
 6. A kit according to claim 2, said bismuth complexercomprising sodium nitrilotriacetate.
 7. A kit according to claim 1, saidfirst composition comprising nickel sulfate.
 8. A kit according to claim1, said reducing agent being selected from the group consisting ofsodium, potassium, and ammonium hypophosphite.
 9. A kit according toclaim 2, said first composition comprising nickel sulfate.
 10. A kitaccording to claim 2, said reducing agent being selected from the groupconsisting of sodium, potassium, and ammonium hypophosphite.
 11. A kitaccording to claim 2, said second composition further comprising atleast one of a pH buffer and an anti-pit agent, said kit furthercomprising a third container containing a third composition, said thirdcomposition comprising a reducing agent and at least one of a pH bufferand an anti-pit agent, the proportion of said reducing agent to said atleast one of buffer and anti-pit agent being different from theproportion of reducing agent to said at least one of buffer and anti-pitagent in said second composition.
 12. A method of preparing anelectroless nickel plating composition, the method comprising: providinga kit, said kit comprising a first container containing a firstcomposition and a second container containing a second composition, saidfirst composition containing nickel and said second compositioncontaining a reducing agent, said first and second compositions beingcombinable to form an electroless nickel plating composition; and mixingsaid first composition with said second composition to form anelectroless nickel plating composition; said first compositioncontaining a surfactant-brightener, said surfactant-brightener beingpresent in an amount effective to enhance luster of an object platedwith said electroless nickel plating composition, and a coupler, saidcoupler being present in an amount effective to inhibit oil-out of saidsurfactant-brightener.
 13. A method according to claim 12, saidsurfactant-brightener being selected from the group consisting of nonyland octyl-phenoxypolyethoxyethanol surfactants having an HLB rangingfrom about 12.0 to about 18.0.
 14. A method according to claim 12, saidcoupler being selected from the group consisting of naphthalenesulfonates.
 15. A method according to claim 12, said first compositioncomprising nickel sulfate.
 16. A method according to claim 12, saidreducing agent being selected from the group consisting of sodium,potassium, and ammonium hypophosphite.
 17. A method for forming anelectroless nickel plating composition, comprising; providing a kit,said kit comprising a first container containing a first composition anda second container containing a second composition, said firstcomposition containing nickel and said second composition containing areducing agent, said first and second compositions being combinable toform an electroless nickel plating composition; said second compositioncontaining a bismuth metallic stabilizer in an amount effective toinhibit plate-out of said electroless nickel plating composition, and abismuth complexer, said bismuth complexer being present in an amounteffective to inhibit precipitation of bismuth; and mixing said firstcomposition and said second composition to form an electroless nickelplating composition.
 18. A method according to claim 17, said secondcomposition further containing an organosulfur stabilizer in an amounteffective to inhibit plate-out of said electroless nickel platingcomposition.
 19. A method according to claim 17, said bismuth complexercomprising sodium nitrilotriacetate.
 20. A method according to claim 17,said first composition comprising nickel sulfate.
 21. A method accordingto claim 17, said reducing agent being selected from the groupconsisting of sodium, potassium, and ammonium hypophosphite.
 22. Amethod comprising: providing an electroless nickel plating composition,said composition comprising nickel; a reducing agent; asurfactant-brightener, said surfactant-brightener being present in anamount effective to enhance luster of an object plated with saidelectroless nickel plating composition; and a coupler, said couplerbeing present in an amount effective to inhibit oil-out of saidsurfactant-brightener; and introducing an object to said electrolessnickel plating composition under conditions suitable to cause nickelplating on a surface of said object.
 23. A method according to claim 22,further comprising replenishing said electroless nickel platingcomposition with a composition that comprises a reducing agent and atleast one of a pH buffer and an anti-pit agent.
 24. A method comprising:providing an electroless nickel plating composition, said compositioncomprising nickel; a reducing agent; a bismuth metallic stabilizer, saidbismuth metallic stabilizer being present in an amount effective toinhibit plate-out of said electroless nickel plating composition, themass of nickel in said composition exceeding the mass of bismuth; and abismuth complexer, said bismuth complexer being present in an amounteffective to inhibit precipitation of bismuth; and introducing an objectto said electroless nickel plating composition under conditions suitableto cause nickel plating on a surface of said object.
 25. A methodaccording to claim 24, said electroless nickel plating compositionfurther containing an organosulfur stabilizer in an amount effective toinhibit plate-out of said electroless nickel plating composition.
 26. Amethod according to claim 25, said bismuth complexer comprising sodiumnitrilotriacetate.
 27. A method according to claim 24, said reducingagent being selected from the group consisting of sodium, potassium, andammonium hypophosphite.
 28. A method according to claim 24, the methodfurther comprising replenishing said electroless nickel platingcomposition with a composition that comprises a reducing agent and atleast one of a pH buffer and an anti-pit agent.